Impingement syndrome of the ankle following supination external rotation trauma: MR imaging findings with arthroscopic correlation

Our objective was to identify MR imaging findings in patients with syndesmotic soft tissue impingement of the ankle and to investigate the reliability of these imaging characteristics to predict syndesmotic soft tissue impingement syndromes of the ankle. Twenty-one ankles with chronic pain ultimately proven to have anterior soft tissue impingement syndrome were examined by MR imaging during January 1996 to June 2001. The MR imaging protocol included sagittal and coronal short tau inversion recovery (STIR), sagittal T1-weighted spin echo, axial and coronal proton-density, and T2-weighted spin-echo sequences. Nineteen ankles that underwent MR imaging during the same period of time and that had arthroscopically proven diagnosis different than impingement syndrome served as a control group. Fibrovascular scar formations distinct from the syndesmotic ligaments possibly related to syndesmotic soft tissue impingement were recorded. Arthroscopy was performed subsequently in all patients and was considered the gold standard. The statistical analysis revealed an overall frequency of scarred syndesmotic ligaments of 70% in the group with ankle impingement. Fibrovascular scar formations distinct from the syndesmotic ligaments presented with low signal intensity on T1-weighted images and remained low to intermediate in signal intensity on T2-weighted MR imaging. Compared with arthroscopy, MR imaging revealed a sensitivity of 89%, a specificity of 100%, and a diagnostic accuracy of 93% for scarred syndesmotic ligaments. The frequency of scar formation distinct from the syndesmotic ligaments in patients with impingement syndrome of the ankle was not statistically significantly higher than in the control group. In contrast to that, anterior tibial osteophytes and talar osteophytes were statistically significantly higher in the group with anterior impingement than in the control group. Conventional MR imaging was found to be insensitive for the diagnosis of syndesmotic soft tissue impingement of the ankle. Fibrovascular scar tissue distinct from syndesmotic ligaments is suggestive for the diagnosis of soft tissue impingement, but the reliability of these findings is still questionable. Electronic Publication     

Ankle MRI for anterolateral soft tissue impingement: increased accuracy with the use of contrast-enhanced fat-suppressed 3D-FSPGR MRI

OBJECTIVE: To validate the use of contrast-enhanced (CE) fat-suppressed three-dimensional (3D) fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance imaging (MRI) for the diagnosis of anterolateral soft tissue impingement of the ankle, as compared to the use of routine ankle MRI. MATERIALS AND METHODS: Contrast-enhanced fat-suppressed 3D-FSPGR MRI and routine MRI scans were retrospectively reviewed for 45 patients with arthroscopically proven anterolateral impingement. In addition, scans were reviewed in 45 control subjects with diagnoses other than impingement. Two radiologists independently reviewed the two sets of images in random order. Using areas (Az) under the receiver operating characteristic curve (ROC), we compared the depiction of anterolateral soft tissue impingement in the two sets of images. RESULTS: The overall accuracy for lesion characterization was significantly higher (p < 0.05) using the CE fat-suppressed 3D-FSPGR MR images (Az = 0.892 and 0.881 for reader 1 and 2, respectively) than using the routine MR images (Az = 0.763 and 0.745). The use of CE fat-suppressed 3D-FSPGR MRI enhanced impingement depiction in most cases. However, in cases with a thickened non-enhancing scar or joint effusion, the routine images better depicted a soft tissue mass that intruded into anterolateral gutter than the CE images. CONCLUSION: The use of CE fat-suppressed 3D-FSPGR MRI of the ankle allows a more accurate assessment of anterolateral soft tissue impingement of the ankle, as compared to the use of routine MRI.     

Magnetic resonance imaging findings in anterolateral impingement of the ankle

Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle. Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group. Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter. Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. Received: 22 July 1999 Revision requested: 20 September 1999 Revision received: 7 October 1999 Accepted: 8 October 1999     

Treatment of anterolateral impingements of the ankle joint by arthroscopy

Impingement syndromes of the ankle joint are among the most common intraarticular ankle lesions. Soft tissue impingement lesions of the ankle usually occur as a result of synovial, or capsular irritation secondary to traumatic injuries, usually ankle sprains, leading to chronic ankle pain. The aim of this prospective study was to evaluate arthroscopic debridement of an anterolateral soft tissue impingement of the ankle. During the period between October 2000 and February 2004, 23 patients with residual complaints after an ankle sprain were diagnosed as anterolateral impingement of the ankle, and were treated by arthroscopic debridement. At a minimum of 6 months follow up, patients were asked to complete an American orthopaedic foot and ankle society (AOFAS) ankle and hind foot score. The average follow-up was 25 months (range 12–38). The average pre-operative patient assessed AOFAS score was 34 (range 4–57). At the end of follow-up the mean AOFAS score was 89 (range 60–100). In terms of patient satisfaction 22 patients said they would accept the same arthroscopic procedure again for the same complaints. At the end of follow-up, 7 patients had excellent results, and 14 patients had good results while two patients had fair results. We believe that arthroscopic debridement of the anterolateral impingement soft tissues are a good, and effective method of treatment.     

The MR imaging features of the posterior intermalleolar ligament in patients with posterior impingement syndrome of the ankle

Objective. To describe the MR imaging features of the posterior intermalleolar ligament (IML) in patients with posterior impingement syndrome (PIS) of the ankle. Design and patients. Three patients (one male and two females, 13–25 years of age) are presented. Each patient presented clinically with symptoms of PIS of the ankle. Plain film examination was negative for a structural cause of the PIS in all patients. MR images were obtained with a 1.5 T scanner using an extremity coil. Clinical data and, in one patient, findings at ankle arthroscopy, were correlated with the results of MR imaging. Results. Ankle MR images from the three patients with a clinical diagnosis of PIS are presented. Findings in all patients included: (1) absence of another structural cause of the PIS (i.e., an os trigonum, trigonal process, fracture, loose bodies, etc.), (2) identification of the IML as a structure discrete from the posterior talofibular and tibiofibular ligaments, and (3) prominence of the IML as indicated by (a) identification of the IML in three different imaging planes, and (b) a caliber of the IML comparable to that of the conventional posterior ankle ligaments visualized in the same imaging plane. Arthroscopic resection of a meniscoid IML resulted in resolution of the PIS in one of the patients presented. Conclusions. MR imaging is an effective means of investigating the IML as a potential cause of PIS. The identification of a prominent IML in the absence of another structural cause of PIS indicates that impingement of the IML is the most likely cause of PIS. Received: 11 March 1999 Revision requested: 5 May 1999 Revision received: 2 June 1999 Accepted: 4 June 1999     

The distal fascicle of the anterior inferior tibiofibular ligament as a cause of tibiotalar impingement syndrome: a current concepts review

Impingement syndromes of the ankle involve either osseous or soft tissue impingement and can be anterior, anterolateral, or posterior. Ankle impingement syndromes are painful conditions caused by the friction of joint tissues, which are both the cause and the effect of altered joint biomechanics. The distal fascicle of the anterior inferior tibiofibular ligament (AITFL) is possible cause of anterior impingement. The objective of this article was to review the literature concerning the anatomy, pathogenesis, symptoms and treatment of the AITFL impingement and finally to formulate treatment recommendations. The AITFL starts from the distal tibia, 5 mm in average above the articular surface, and descends obliquely between the adjacent margins of the tibia and fibula, anterior to the syndesmosis to the anterior aspect of the lateral malleolus. The incidence of the accessory fascicle differs very widely in the several studies. The presence of the distal fascicle of the AITFL and also the contact with the anterolateral talus is probably a normal finding. It may become pathological, due to anatomical variations and/or anterolateral instability of the ankle resulting from an anterior talofibular ligament injury. When observed during an ankle arthroscopy, the surgeon should look for the criteria described to decide whether it is pathological and considering resection of the distal fascicle. The presence of the AITFL and the contact with the talus is a normal finding. An impingement of the AITFL can result from an anatomical variant or anteroposterior instability of the ankle. The diagnosis of ligamentous impingement in the anterior aspect of the ankle should be considered in patients who have chronic ankle pain in the anterolateral aspect of the ankle after an inversion injury and have a stable ankle, normal plain radiographs, and isolated point tenderness on the anterolateral aspect of the talar dome and in the anteroinferior tibiofibular ligament. The impingement syndrome can be treated arthroscopically.     

Arthroscopic treatment of impingement of the ankle reduces pain and enhances function

A consecutive series of 105 patients with a median age of 35 (16-62) years who were operated on with arthroscopic resection for impingement of the ankle using standardized technique without distraction is presented. All patients complained of painful dorsiflexion and had failed to respond to conservative treatment. A total of 177 diagnoses were found, soft tissue impingement or synovitis in 89, anterior bony impingement in 44, chondral lesion in 20, loose bodies in 16 and osteoarthritis in eight. At follow-up after 2 years, 65 patients were pain free while 28 patients had experienced reduction of pain. Gait was improved in 30/41 patients and 22 resumed sporting activities. The results were graded excellent in 67, good in 25, fair in six and poor in seven patients. There were four deep infections and one synovial fistula in this series. The deep infections all responded well to arthroscopic synovectomy and intravenous antibiotics. In one patient persistent symptoms were recorded. Ankle arthroscopy yielded good results in the treatment of anterior impingement of the ankle as it effectively reduced pain and enhanced function.     

踝关节前外侧软组织撞击综合征的MRI评价研究

目的:探讨MRI在踝关节前外侧软组织撞击综合征中的评价价值。方法:回顾性分析经临床、影像证实的踝关节前外侧软组织撞击综合征15例患者的MRI表现,主要观察踝关节前外侧沟内软组织、距腓前韧带、距腓前韧带前方脂肪、距腓前韧带旁积液等。结果:①踝关节前外侧沟内软组织影均不同程度增厚2～5mm(占100%);②距腓前韧带断裂9例(占60%),部分断裂2例(占13%),不能明确4例(占27%);③踝关节前外侧皮下脂肪影明显变薄10例(占67%),有不连续表现5例(占33%);④距腓前韧带旁明显积液11例(占73%),液体少4例(占27%);⑤滑膜增厚1例(占7%),无滑膜增厚14例(占93%);⑥胫骨远端骨髓水肿1例,距骨骨髓水肿3例,多个骨骨髓水肿1例。结论:MRI是评价踝关节前外侧软组织撞击综合征的最佳方法,能够清晰显示踝关节前外侧软组织病损情况及其他合并病变,可为临床诊断及治疗提供充分的资料。     

MRI features of posterior ankle impingement syndrome in ballet dancers: a review of 25 cases

AIM: To describe the magnetic resonance imaging (MRI) features of posterior ankle impingement syndrome (PAIS) in classical ballet dancers. MATERIALS AND METHODS: A retrospective review was undertaken of 25 MRI examinations of the ankle performed on 23 ballet dancers over a 26-month period. Images were examined for the presence of osseous and soft-tissue anatomical variants at the posterior ankle and imaging signs of PAIS. All patients presented with symptoms and signs suggestive of PAIS including posterior ankle pain, swelling and stiffness during plantar flexion. RESULTS: Anatomical variants predisposing to PAIS including as os trigonum and tuberosity arising from the superior calcaneum were clearly depicted. The most common imaging feature of PAIS in our series was high T2 signal posterior to the talocalcaneal joint indicating synovitis (n = 25). Thickening of the posterior capsule (n = 13) and tenosynovitis of flexor hallucis longus (n = 17) were also common. An os trigonum was an infrequent finding (n = 7). Bone marrow oedema, commonly in the posterior talus (n = 10) or in a patchy distribution (n = 10) was often noted. CONCLUSION: MRI is a useful diagnostic tool in PAIS, and in the present series, clearly demonstrates the anatomical variants and range of osseous and soft-tissue abnormalities associated with this condition. Prospective studies are needed to understand the significance and importance of individual MRI findings in producing the symptoms of PAIS.     

Soft-tissue and osseous impingement syndromes of the ankle: role of imaging in diagnosis and management.

Soft-tissue and osseous impingement syndromes of the ankle can be an important cause of chronic pain, particularly in the professional athlete. The main impingement syndromes are anterolateral, anterior, anteromedial, and posterior impingement. These conditions arise from initial ankle injuries, which, in the subacute or chronic situation, lead to development of abnormal osseous and soft-tissue thickening within the ankle joint. The relative contributions of the osseous and soft-tissue abnormalities are variable, but whatever component is dominant there is physical impingement and painful limitation of ankle movement. Conventional radiography is usually the first imaging technique performed and allows assessment of any potential bone abnormality, particularly in anterior and posterior impingement. Computed tomography (CT) and isotope bone scanning have been largely superseded by magnetic resonance (MR) imaging, but the accuracy and role of MR imaging in assessment of possible ankle impingement have not been clearly established. MR imaging can demonstrate osseous and soft-tissue edema in anterior or posterior impingement. Studies of conventional MR imaging have produced conflicting sensitivities and specificities in assessment of anterolateral impingement. CT and MR arthrographic techniques allow the most accurate assessment of the capsular recesses, albeit with important limitations in diagnosis of clinical impingement syndromes.     

Benefits of arthroscopic tuberculoplasty in posterior ankle impingement syndrome

The purpose of this work was to describe the posterior ankle impingement syndrome related to the posterolateral tubercle of the talus bone and to present a retrospective analysis of our results after arthroscopic plasty of the tubercle in 15 ankles with a mean 3-year follow-up. Fifteen cases of posterior ankle impingement (PAI) underwent arthroscopic excision of an impinging bone spur. All the patients (13) were retrospectively evaluated at an average of 36 months after index surgery. There were seven women (bilateral in two of them) and six men. Ten were involved in different kinds of sport and three were professional ballet dancers. Preoperative symptoms included pain localized in the posterior ankle, limitation of motion, weakness and swelling. All patients had failed a course of conservative therapies. Surgery was performed through posterolateral and posteromedial portals as described by van Dijk. After soft tissue debridement, partial resection of the posterolateral process was performed until there was complete plantar flexion without bone impingement. Postoperatively, all patients followed the same rehabilitation protocol. Improvement in their impingement symptoms was recorded in all of them according to AOFAS score. One of them (7%) still had occasional discomfort. The results suggest that arthroscopic bone decompression of the posterolateral tubercle in cases of PAI resistant to non-surgical therapies is an effective treatment.     

Anteromedial impingement of the ankle: using MR arthrography to assess the anteromedial recess

OBJECTIVE: Our objective was to describe the appearance of the anteromedial tibiotalar joint on MR arthrography in patients with clinically and arthroscopically confirmed anteromedial impingement. CONCLUSION: Anteromedial impingement of the ankle is now being recognized in the orthopedic literature as a distinct entity. MR arthrographic findings of anteromedial impingement include capsular and synovial soft-tissue thickening anterior to the tibiotalar ligaments and any associated osseous abnormality. Although anteromedial impingement is uncommon compared with other impingement syndromes of the ankle, the radiologist should be aware of the diagnosis and possible findings on cross-sectional imaging.     

Synovitis and soft tissue impingement of the ankle: assessment with enhanced three-dimensional FSPGR MR imaging

PURPOSE: To assess soft tissue impingement as well as synovitis of the ankle associated with trauma by using contrast-enhanced (CE), fat-suppressed, three-dimensional, fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance (MR) imaging. MATERIALS AND METHODS: A total of 36 patients who had had chronic ankle pain associated with a traumatic injury undertook fat-suppressed CE three-dimensional FSPGR MR imaging and then arthroscopy of the ankle. The ankle joint was divided into four compartments by anatomic details: the anterolateral gutter, anteromedial gutter, anterior recess, and posterior recess. Synovial enhancement was graded as follows: grade I, no enhancement; grade II, linear enhancement; grade III, focal nodular enhancement; and grade IV, irregular nodular enhancement. MR grading of the synovial enhancement (synovitis, grade III or IV; soft tissue impingement, grade III or IV with its intrusion from the capsular reflection) was compared with arthroscopic findings. A control study of twenty asymptomatic ankles was done for determining enhancement. Arthroscopy confirmed synovitis in 47 compartments of 27 patients. Of the 27 patients, 15 revealed soft tissue impingement in 17 compartments. RESULTS: For the assessment of synovitis, fat-suppressed CE three-dimensional FSPGR MR imaging had an accuracy of 72.9%, sensitivity of 91.5%, and specificity of 63.9%; whereas for that of soft tissue impingement it had an accuracy of 94.4%, sensitivity of 76.5%, and specificity of 96.9%. All of the asymptomatic subjects showed grade I (81%) or II (19%) synovial enhancement. CONCLUSION: Fat-suppressed CE three-dimensional FSPGR MR imaging was sensitive for the evaluation of synovitis of the ankle associated with trauma, whereas it was specific for soft tissue impingement evaluation.     

Anterior ankle impingement syndromes

Ankle impingement syndromes are painful conditions that may complicate ankle trauma and are characterized by chronic, progressive pain, swelling, and limitation of movement. These disorders are subclassified according to anatomical location about the tibiotalar joint. This article reviews the various forms of anterior ankle impingement, detailing the unique clinical features, anatomical considerations, pathoetiology, and imaging findings for each.     

Clinical outcome of the arthroscopic management of sports-related “anterior ankle pain”: a prospective study

Anterior impingement syndrome is a generally accepted diagnosis for a condition characterized by anterior ankle pain with limited and painful dorsiflexion. The cause can be either soft tissue or bony obstruction. We reviewed 26 (16 male and 10 female) athletes with a mean age of 27 years treated arthroscopically for symptoms due to soft-tissue (group I, n = 12) and bony obstruction (group II, n = 14). They suffered from anterior pain, reduction of dorsiflexion and recurrent swelling with severe impairment in their sports activities. There was no clinical improvement for at least 6 months despite of conservative treatment with a mean duration of symptoms about 20 months. There were no further operations. Evaluation included the Karlsson ankle rating score, the activity score of Tegner, and a visual analogue scale (VAS) reflecting patients’ pain. Conventional radiographs and Magnetic resonance imaging (MRI) were done preoperatively. All patients were available for follow up after 31 months (range, 25–48 months) with a significant improvement (p < 0.05) of the Karlsson score from 66 to a mean of 92 at the follow-up examination. The mean Tegner score was eight points compared to three points preoperatively. Regarding the subjective assessment observed by the decrease of pain and the ability of the athelete to return to competition sport, there were 25 very satisfied and one unsatisfied athlete. No significant difference in the outcome of group I and II (p > 0.05) could be estimated. The results demonstrate ’ excellent ’ to ’ good ’ results for arthroscopic treatment of sports-related anterior ankle pain in a group of athletes who were involved in competition sport. The promising clinical results confirm an effective way of treating soft-tissue and bony impingement. In addition, we recommend prior to surgery, an adequate course of non-operative treatment, including modifications in the exercise program and athletic activity.     

MRI appearance of surgically proven abnormal accessory anterior–inferior tibiofibular ligament (Bassett’s ligament)

Objective A thickened accessory anterior–inferior tibiofibular ligament (Bassett’s ligament) of the ankle can be a cause of ankle impingement. Its imaging appearance is not well described. The purpose of this study was to determine if the ligament could be identified on magnetic resonance imaging (MRI), to determine associated abnormalities, and to determine if MRI could be used to differentiate normal from abnormal. Materials and methods Eighteen patients with a preoperative ankle MRI and an abnormal Bassett’s ligament reported at surgery were found retrospectively. A separate cohort of 18 patients was selected as a control population. The presence of Bassett’s ligament and its thickness were noted. The integrity and appearance of the lateral ankle ligaments, talar dome cartilage, and anterolateral gutter were also noted. Results In 34 of the 36 cases (94%), Bassett’s ligament was identified on MRI. The ligament was seen in all three imaging planes and most frequently in the axial plane. The mean thickness of the ligament in the surgically abnormal cases was 2.37 mm, compared with 1.87 mm in the control with a p value = 0.015 (t test). Nine of the 18 abnormal cases (50%) had talar dome cartilage lesions as a result of contact with the ligament at surgery, with only 3 cases of high-grade defects seen on MRI. Fourteen of the 18 abnormal cases (78%) had of synovitis or scarring in the lateral gutter at surgery, with only 5 cases with scarring seen on MRI. The anterior–inferior tibiofibular ligament was abnormal or torn in 8 of the 18 abnormal cases (44%) by MRI and confirmed in only 3 cases at surgery. Discussion Bassett’s ligament can be routinely identified on MRI and was significantly thicker in patients who had it resected at surgery. An abnormal Bassett’s ligament is often present in the setting of a normal anterior–inferior tibiofibular ligament. The cartilage abnormalities and synovitis associated with an abnormal Bassett’s ligament are poorly detected by conventional MRI.     

Imaging in the assessment and management of overuse injuries in the foot and ankle

Overuse injuries of the ankle and foot are common in the general and athletic populations. The wide spectrum of overuse injuries includes ligamentous injuries, soft tissue and osseous impingement, osteochondral lesions, tendon injuries, and stress fractures. Some conditions such as impingement syndromes and stress fractures may be missed on initial physical examination, and patients with such injuries often present to a sports or orthopedic clinic with persistent symptoms. With the increasing participation in sports, health-care professionals involved in the care of athletes at all levels must have a thorough understanding of overuse conditions of the foot and ankle, and the use of imaging in the management of these conditions. This article covers the clinical presentation, pertinent anatomy, imaging features, and management of overuse injuries of the foot and ankle.     

Ankle impingement syndromes

The term "ankle impingement" encompasses a broad range of conditions that are typically post-traumatic and often chronic. Various forms of mechanical impingement can result from synovial proliferation, bone spur formation, or ligamentous scarring and hypertrophy. Since symptoms and physical findings can mimic a variety of disorders, accurate diagnosis may remain elusive, and proper effective therapy may be delayed. The objective of this article is to define and elucidate the etiology of the various forms of ankle impingement, clarify the range of associated osseous and soft-tissue pathology, and describe the imaging features and therapeutic options.     

Subacute posteromedial impingement of the ankle in athletes: MR imaging evaluation and ultrasound guided therapy

Objective To describe the use of MR imaging and efficacy of ultrasound-guided steroid injection in the diagnosis and management of athletes with clinical posteromedial impingement of the ankle. Design and patients A retrospective analysis of imaging findings on MR was undertaken in nine elite athletes with clinical posteromedial ankle impingement. MR studies from six professional athletes with posterolateral pain were also reviewed as an imaging control group. The two reviewing radiologists were blinded to the clinical details and the proportion of control and study subjects. The nine study athletes also underwent diagnostic ultrasound and ultrasound-guided injection of steroid and anaesthetic into the posteromedial capsular abnormality. Follow-up was by telephone interview. Results Posteromedial capsular thickening was seen only in athletes with posteromedial impingement (7/9). Posteromedial synovitis was present in all athletes with posteromedial impingement; however, posterior and posterolateral synovitis was also seen in these athletes. Mild posteromedial synovitis was present in two control athletes. Ultrasound identified abnormal posteromedial soft tissue thickening deep to tibialis posterior between the medial malleolus and talus in all nine athletes. After injection all athletes returned to their previous level of sport, with eight of the nine not experiencing any residual or recurrent symptoms. Conclusion If MR imaging excludes significant coexistent abnormality, ultrasound can localise posteromedial soft tissue abnormality and guide injection therapy, allowing return to athletic activity without surgical intervention.     

Posterior impingement syndromes of the ankle.

Acute, or repetitive, compression of the posterior structures of the ankle may lead to posterior ankle impingement (PAI) syndrome, posteromedial ankle impingement (PoMI) syndrome, or Haglund's syndrome. The etiology of each of these conditions is quite different. Variations in posterior ankle osseous and soft tissue anatomy contribute to the etiology of PAI and Haglund's syndromes. The presence of an os trigonum or Stieda process is classically associated with PAI syndrome, whereas a prominent posterosuperior tubercle of the os calcis or Haglund's deformity is the osseous predisposing factor in Haglund's syndrome. PoMI has no defined predisposing anatomical variants but typically follows an inversion-supination injury of the ankle joint. This article discusses the biomechanics, clinical features, imaging, and management of each of these conditions. Magnetic resonance imaging (MRI) provides the optimal tool in posterior ankle assessment, and this review focuses on the MRI findings of each of the conditions just listed.